How did life start?

K

Knowledge

Registered Member
This classic question of life have been around for many centruies. Do we or do we not have the answer?

To answer this question, we have to go back in time, to find out how did your planet become habitable for life forms to emerge.

about 2.3 billion years ago unusual microbes breathed new life into young planet Earth by filling its skies with oxygen. Without thoes prolific organisms, called cyanobacteria, most of the life that we see around us would never be evolved.

How ever, this only answers life before Oxygen. How did life really started is what I am trying to find out.

Let all of you, the great thinkers, philosophers, and scientists help to answer my question, or at least open your precious mind, share with me about ur thoughts on how did life start
 
Other theories include the idea that clay surfaces originally catalysed the reactions which led to the first living cells or self-replicating nucleic acids;

that primitive organisms are widespread throughout the Galaxy, and were deposited on the early Earth by meteorites (or deliberately seeded by ancient alien intelligence);

that the first living cell arose spontaneously by a totally random molecular sorting process, so improbable that it cannot be reasonaby expected anywhere else in the Universe;

that God did it!
 
It was probably a totally random process (1 in a couple of billion) but what it created was a molecule which had the ability to replicate. these molecules sread far and wide and then evolved through natural selection.

The probability figure I mentioned above certainly does not mean it can't happen in this universe. I'm sure there's quite a bit of ET life in our galaxy alone.
 
John Connellan said:
The probability figure I mentioned above certainly does not mean it can't happen in this universe. I'm sure there's quite a bit of ET life in our galaxy alone.
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I hope so. In fact, it may be that life arose several times here on Earth, independently in different environments: warm pools (perhaps tidal) as you said before, hydrothermal vents on the ocean floor, the chemical-rich surface of the early seas, and hydrocarbon/water pockets far underground.

If the last of these is true, then deep hot biospheres may exist within planets whose surfaces are completely uninhabitable - such as Mercury, Venus, even our Moon. A subterranean genesis mechanism would allow life to be far more ubiquitous in the Galaxy than one which requires surface oceans and a narrow temperature range.

A reasonable summary of current majority thinking on biogenesis.
 
Starthane Xyzth said:
I hope so. In fact, it may be that life arose several times here on Earth, independently in different environments:
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Yes, I was going to mention that but i didn't! It is even likely that the first cell formed and was destroyed so that life had to wait a couple of times like this for these random events to happen before it got irreversibly started (and diverse).
 
Yes, it's quite right that the early life forms were formed by the RNAs and DNAs, which early RNA turn into DNA, then slowly turn into simple life forms. But how did RNA form? it it was carried from outter space, from another place....how can it withstand such temperture to enter Earth? and what makes it copy itself?
 
Knowledge said:
Yes, it's quite right that the early life forms were formed by the RNAs and DNAs, which early RNA turn into DNA, then slowly turn into simple life forms. But how did RNA form? it it was carried from outter space, from another place....how can it withstand such temperture to enter Earth? and what makes it copy itself?
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Like I said already, replication is not unique to living organisms. It is not that special really!

Eigen, M.: 1971, Self-Organization of Matter and the Evolution of Biological Macromolecules, Naturwissenschaften 58, 465–523.

Joyce, G. F.: 1994, In Vitro Evolution of Nucleic Acids, Curr Opin. Struct. Biol. 4, 331–6.

Orgel, L. E.: 1992, Molecular Replication, Nature 358, 203–209.

Spiegelman, S.: 1967, An In Vitro Analysis of a Replicating Molecule, American Scientist 55, 221–64.
 
Kumar said:
Btw, is there any life in atoms or sub-atomic particles?
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Life to many means a living organism. I wouldn't think that these would be called "life forms" but are the precursor to life for without them life cannot exist as humans know it.
 
cosmictraveler said:
Life to many means a living organism. I wouldn't think that these would be called "life forms" but are the precursor to life for without them life cannot exist as humans know it.
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Not really, many people think of cells as being alive. Certainly scientists do.
 
cosmictraveler said:
Life to many means a living organism. I wouldn't think that these would be called "life forms" but are the precursor to life for without them life cannot exist as humans know it.
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We may just be a cluster of these basic lives. Is it in evolution that these sub-atomic particles got life/energy at some time & these also mulitiplied?
 
I view life as a force akin to gravity in the sense that gravity seems fundamental to the structure of the universe. Apparently under certain chemical conditions, this force expresses and perpetuates itself. It's sort of "anti-entropy" IMO. Regardless, apparently the proper chemical conditions occured at random, resulting in the allowance of the life-force to express itself. Its expression is survival on the individual level, which through random processes expresses itself across entire species, since that "group" level survival tends to lend to the survival of the individual, which then propogates (in keeping with the life-force) to the expansion of the species, etc.

I'm not sure if "force" is really the proper term of course, but that's just the easiest way for me to see it. It seems to me to be correct.

Basically, random conditions led to allowance of a previously untapped force; "that which makes things be alive", which itself mandates to continue to be alive and make more life - resulting in the plethora of life around us today.

It's probably safe to assume that this force was randomly allowed to express itself in many different locations throughout the universe. The success of continued survival in each instance is unknown except on earth, but it seems quite likely (if this analysis has any merit) that it must have been successful at other locations.
 
Knowledge said:
Then what do u concider alive? can u define life?
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Life is what seperates animals and plants from rocks.

There are definitions of life which include the ability to respire, reproduce genetically, metabolise (linked with respiration), maintain homeostasis etc. they are in the first chapter of a biology book and I'm not going to bother remembering them all :D
 
John Connellan said:
No, the atoms themselves are not alive.
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One Dict.Definition of life is: the period of existence (as of a subatomic particle) -- compare HALF-LIFE.

If we want to understand 'How life starts' we may need to understand life in atoms or sub-atomic particles. However "vitalism" is relevant to as you said.
 
Kumar said:
One Dict.Definition of life is: the period of existence (as of a subatomic particle) -- compare HALF-LIFE.
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I believe the context of this thread was biological life... which, as John C. said, must fulfill a series of basic functions. As far as I recall, those are: nutrition, respiration, reproduction, sensation and excretion. (Some say locomotion as well, but I don't think that's necessarily so - many organisms, especially microbes, can stay in the same spot all their lives.)

You could say that individual atoms, under some circumstances, can "feed" on stray neutrons or alpha particles; "excrete" radiation and electrons, "sense" external forces such as UVs and change their energy levels accordingly. They do not respire, however, and they do not reproduce their own kind: daughter atoms from radioactive decay are, obviously, of different elements.
 
Starthane Xyzth said:
I believe the context of this thread was biological life... which, as John C. said, must fulfill a series of basic functions. As far as I recall, those are: nutrition, respiration, reproduction, sensation and excretion. (Some say locomotion as well, but I don't think that's necessarily so - many organisms, especially microbes, can stay in the same spot all their lives.)

You could say that individual atoms, under some circumstances, can "feed" on stray neutrons or alpha particles; "excrete" radiation and electrons, "sense" external forces such as UVs and change their energy levels accordingly. They do not respire, however, and they do not reproduce their own kind: daughter atoms from radioactive decay are, obviously, of different elements.
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Thanks for good reply. If we want to talk start from biological life then it is ok, but the basis will be somewhat alike:
Energy>>matter+energy>>sub-atomic particles>>atom(H)>>complex atoms>>elements>>molecules>>first biological life>>complex/higher biological life>>multoplications>>>>>>>>>>may be restart. :)

Is it not a simple & logical understanding. Cosmology in evolution/ Darwin's theory somewhat indicates it.

Some ancient studies indicate life in atoms as 'one sense life' alongwith air,water,space,earth & fire.

What & how atoms do somewhat alike biological activities(some you mentioned) can be a good thought for discussion. :m:
 
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